They said, Group Captain Arun Marwah posted at the IAF headquarters here, was handed over to Delhi Police on Wednesday after nearly 10 days of questioning by the counter- intelligence wing of the force.
"The Delhi Police will now carry forward the probe. The officer has been slapped charges under Official Secrets Act," said a source.
The officer was allegedly leaking classified documents to a woman through WhatsApp.
Sources said he had befriended the woman through a social media website.
The investigators from IAF's counterintelligence wing were also probing whether he was part of a larger espionage ring being run from Pakistan, the sources said.
According to multiple media reports, Marwah was honey-trapped by the ISI through Facebook accounts in mid-December. ISI operatives were impersonating as models through these profiles. Marwah was lured through seductive conversations for a week or so, after which he was persuaded to share information pertaining to IAF exercises.
Marwah has been sent to five days' police custody and is being interrogated by the authorities.
Marwaha's phone has been confiscated and sent for forensic examination.
Reports stated that he has admitted to having had access to many secret documents and plans due to his posting at the air headquarters.
The officer was indulging in certain "unwanted activities" through unauthorised electronic devices which is against existing orders, sources had said.The IAF officially did not comment on the matter.
Punishment under Official Secrets Act entails a jail term of up to seven years.